06/07/07 FCST: TX / OK / KS / MO / IA / IL / WI

[David Draun]

HIGH RISK NEAR CHICAGO, TOO CLOSE FOR COMFORT!

Woah, that high risk area was shifted south since I last looked! It's practically on Dekalb now.

Looks like the show could begin early with that MD out in Iowa/Minnesota. Parameters already coming together. Mesoanalysis shows the strong cap begining to weaken already. LI starting to approach -6 and SBCAPE around 1000 J/kg. Supercell composites are at about 4.0. I still don't think these are tornado hodographs on the soundings. Way too unidirectional. I do believe there may be a nasty tornado or two if something can move to the right of the wind flow, maybe through the assistance of an outflow boundary. But most of all, someone is going to get smacked with a nasty derecho event. And I don't believe the Cook county "storm deflector" is going to stop it. With highs over the risk area in the 80's and 90's, dewpoints may mix out a whole lot too. It will be interesting for someone though. I'm not chasing today because of the fast cell motions and the likely linear nature of things in my area. Lacrosse, WI wouldn't be a bad target today to get on good storms. Terrain is probably an issue though. I've been through that area, lots of hills and water all around.

Satellite animation showing some interesting lines of clouds beginning to show up, and a few thunderstorms in Iowa.

 

[Danny Murphy]

I echo your sentiments on the cloud cover. It is currently overcast, for the most part, in NE Iowa. These clouds need to break away and the sky needs to heat up. At least todays chase will be close to home.

Well.. Not surprised at all with the high risk.. Only concern for me is the cloud cover possibly limiting heating across the area.. Other than that. All systems are go for a dangerous severe weather outbreak later today and tonight.. Again, all be safe and good luck chasing!!!

 

[Billy Griffin]

Oklahoma looks like a write-off for today. Take a look at the mesonet data - winds have veered out of the SW and TDs are dropping rapidly. Unidirectional shear tells me, if anything, rapidly screaming squall line through eastern OK into Arkansas. This whole damn thing may wind up being the squall line of the century before the day's over -- from north central Texas to Michigan! Was hoping for a "sleeper" here around OKC today, but my confidence is pretty low at this point.

EDIT: Well, I'll revise my statement in that TDs are remaining ~ 70 east of the dryline, which is impressive. However, I'm still a little disappointed in the veering of the surface winds out of the SW. NE Oklahoma looks okay for now.

 

[Andrew Pritchard]

The thermodynamic set up over Iowa/Missouri/Illinois/Wisconsin is almost perfect, it's too bad the kinematics aren't that great. Pretty good cap over the area holds tight until upper level energy screams into the area right at peak heating and does away with the cap allowing for likely explosive thunderstorm development. Now, were there to be some directional shear, we'd see explosive supercell development with potential long track tornadoes. However as I mentioned before, that just isn't the case right now. We can hope for some isolated areas of better surface flow but as it stands right now I'm guessing we'll see storms develop and become a linear beast within an hour of initiation. Here's to hoping for some freak accident though!

EDIT: Saw some mentioning the stuff already firing in Iowa... figured I would mention that I don't think that is related to the main show, just some elevated convection which is common early on during big event days.

 

[Brandon Goforth]

Well, SPC DAY 1 Outlook seems to pull up tornadic probs down to OK now, but I still expect some change as we go into the afternoon. They seem to question whether or not any activity can develop before dark ahead of the dryline, before the front comes in and things go linear. Although they also mention the growing tornado concern down here in the discussion now...especially mentioning central and south central OK.

 

[Taylor Pechacek]

Chasing Dynamics

Hey All...

I'm lookin at the helicity and vorticity maxima centered near Galena, IL. Maybe I should head farther West than I39/90. Sat pictures also depict some CU fields and MCR in that general vicinity. I'm liking that. Tds are beginning to pool in and along the MS. These are all good signs of storm enhancement.

I'm thinkin a chase target of somethere in Rock or Green Cos, maybe into the Dodgeville area. I like some of the views out that way.

Anyway, thoughts on initiation in Southcentral Wis and Nrn Ill.??

- Taylor

 

[John Farley]

I am still undecided about whether to chase today. I am somewhat constrained in how far I can go today, since I have to set up for an art show tomorrow morning. So I am kind of limited to IL or MO if I do chase. Right now, I like the MO area better than NW IL, where I think the storms are pretty sure to be linear, and of course very fast-moving. There could be tornadoes there, but likely embedded within lines. Not sure MO will be much better, as wind fields are pretty unidirectional there, too, but RUC precip output for this afternoon has been showing tail end of line W or NW of COU. I think the storms, if they develop there before dark, will go pretty linear as well, but the EHI of 5-6 predicted by the RUC in that area around 0:00Z is hard to pass up. I will watch how things evolve for a while and decide later. Probably need to head out by 1:30 or 2 if I do go, though, as this will be a day to be near the point of initiation.

 

[Ben Prusia]

I agree with the SPC's upgrade to moderate risk for severe thunderstorms all the way to central Oklahoma.

Current satellite pictures show cloud cover breaking up over a target area of SE Kansas into Oklahoma as low 70 degree dewpoints are already making their way into the Sunflower State. Still feel initiation will occur at or around 4PM along the dryline that will situate east of the Kansas Turnpike and west of US Highway 75 as the CAP weakens as 700mb temperatures cool. Storms may become supercellular but all depends on the direction of the surface winds, I am still hoping they stay to the south.

The 15Z RUC model still speeds up the system way off to the east by 0Z tonight, but keeping in mind with yesterday, the RUC also sped up the system to hit Grand Island, NE at 0Z today, and did not verify. The 12Z NAM and GFS models still believe and agree that the dryline will be near and along US-169/US-59 in Kansas by 0Z tonight, and looks like those areas will hold a risk of severe thunderstorms tonight.

 

[Brandon Goforth]

Yep, upgrade to moderate risk now all the way through south-central OK with a 10% hatched area for tornado probabilities. This pretty much goes right along with what everyone from this area has been discussing here since the day 1 outlook was released last night. Man, I'm *suppose* to be preparing for a friend's wedding in Texas right now, but no way I'm missing some action in my own back yard.

 

[Jordan Hartley]

I have to agree with Billy on this one. The winds are starting to veer badly now in OK and ever so slightley in SE KS. Im going to tag along with Mike Gribble later today pending that he doesnt change his mind due to that sick veering that is taking place. You know and if the tornado aspect of today doesnt pan out im sure that a nice squall will satisfy me for the day. Last chase of the season for me so im hoping for a miracle

 

[Brandon Goforth]

For you guys worried about the winds veering badly in OK, they are expected to back to the south by mid-afternoon. I'm feeling pretty good about the day in this area right now.

 

[Chris C Sanner]

I'm sitting here at the house mulling where to play today. I'm at the very southern fringe of the MDT but my gut is telling me that the OKC area is in for some interesting weather this evening which wouldn't be the easiest or safest way to chase. I think my initial plan is to try to get somewhere halfway to the metro and hope there is a storm form S. of OKC in the higher instability. I think with the degree of instability and more than adequate wind shear forecasted (which could or could not bust) the biggest question with any storm is how low or high the bases will be in regards to Tornado potential. Some places just ahead of that Dryline are spiking in the mid 90s already in OK.

If the winds back as progged I think theres little doubt the skies will be lighting up owing to better convergence at the dryline. IMHO, I'm sitting and watching and waiting to see when and where this happens. Should be an interesting day weatherwise regardless....

 

[Steve Ryals]

Just a hunch guys, but these are the types of days that seem to turn into straight-line wind, squall line events, but if you like huge hail, then you might want to be out today.

-S.R.

 

[Angie Norris]

Currently sitting at home in Norman. My gut instinct is saying don't move...yet. Despite the fact that none of the models are showing precip anywhere in OK, I'm thinking south of the metro is the place to be. Looked at the surface obs just a few minutes ago, and winds are beginning to back just a hair with winds at OKC and SWO becoming very slightly southerly. I'm guessing OUN launched a 18Z sounding, so will check and see if the cap has favorably changed (was 7.2 on the 12Z...ouch). It would be such a shame to waste all this instability today.

 

[Jeff Piotrowski]

Target Today OKC

I exspect explosive supercell from N-SW of OKC by 21Z with hail in some of storms greater then 3"+ in size. The storms will produce a couple of strong and damaging tornado as they move east.

The greatest threat of tornados after 0Z is from OKC -NE toward Tulsa-SE of OKC toward ADA.

JP.